Bioinformatics-based identification and validation of hub genes associated with aging in patients with coronary artery disease.

Coronary artery disease (CAD) is the most common aging-related disease in adults. We used bioinformatics analysis to study genes associated with aging in patients with CAD. The microarray data of the GSE12288 dataset were downloaded from the Gene Expression Omnibus database to obtain 934 CAD-associated differentially expressed genes. By overlaying them with aging-related genes in the Aging Atlas database, 33 differentially expressed aging-related genes (DEARGs) were identified. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the 33 DEARGs were mainly enriched in cell adhesion and activation, Th17 and Th1/Th2 cell differentiation, and longevity regulation pathways. Hub genes were further screened using multiple algorithms of Cytoscape software and validation set GSE71226. Clinical samples were then collected, and the expression of hub genes in whole blood was detected by real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and western blot at the transcription and translation levels. Finally, HSP90AA1 and CEBPA were identified as hub genes. The results of this study suggest that HSP90AA1 and CEBPA are closely related to CAD. These findings provide a theoretical basis for the association between aging effectors and CAD, and indicate that these genes may be promising biomarkers for the diagnosis and treatment of CAD.

Fifty years of change in the lower tree line in an arid coniferous forest in the Qilian Mountains, northwestern China.

Tree line areas exhibited significant changes in response to climate change, including upward migration. Lower tree line dynamics are rarely studied, but as unique features in arid and semi-arid areas, they may influence forest distribution. Here, eight lower tree line plots in a Picea crassifolia Kom. (Qinghai spruce) forest in the arid and semi-arid Qilian Mountains of northwestern China were used to determine changes in tree line location and relationships with meteorological factors during 1968-2018. The results showed that the lower tree line descended by an average of 9.82 m during 1968 to 2018, and exhibited almost no change after 2008. The change in the lower tree line was significantly correlated with the annual average temperature (°C) and annual precipitation (mm) and may be affected by human activities. In the past 50 years, the lower tree line in arid areas exhibited a downward trend. Our findings indicate that the movement of the lower tree line is also an important aspect of climatic changes in coniferous forest distribution in arid and semi-arid mountains.

Efficacy and Safety of Niraparib as First-Line Maintenance Treatment for Patients with Advanced Ovarian Cancer: Real-World Data from a Multicenter Study in China.

BACKGROUND: Poly (ADP-ribose) polymerase (PARP) inhibitors are a new maintenance therapy option for patients with ovarian cancer (OC). OBJECTIVE: To evaluate the efficacy and influencing factors of the novel PARP inhibitor niraparib for maintenance treatment of Chinese patients with advanced OC. PATIENTS AND METHODS: In this retrospective multicenter real-world study patients with advanced OC from 15 hospitals throughout China were enrolled. The primary endpoint was progression-free survival (PFS) and the secondary endpoints included the time to treatment discontinuation and safety. Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to identify possible risk factors for PFS, after which a prediction model was established to evaluate the likelihood of achieving an 18-month PFS. The relationship between the dose of niraparib and PFS was also evaluated. RESULTS: The PFS rates of 199 patients at 6, 12, 18, 24, and 30 months were 87.4%, 75.9%, 63.6%, 56.1%, and 51.8%, respectively. LASSO regression model revealed that only age < 65 years (P = 0.011), BRCA mutations (P < 0.001), and R0 status after cytoreductive surgery (P = 0.01) were significant factors associated with prolonged PFS times. Based on the LASSO logistic regression analysis, a clinical prediction formula was developed: - 2.412 + 1.396Age≥65yr + 2.374BRCAwt + 1.387R1 + 0.793Interval≥12w + 0.178BMI>24kg/m2 which yielded a cut-off value of 0.091, an area under the curve (AUC) of 0.839 (0.763-0.916), a sensitivity of 94.3%, and an accuracy of 78.5%. A nomogram was then built to visualize the results. The major treatment-emergent adverse events of ≥ grade 3 included a platelet count decrease (19.1%), white blood cell count decrease (15.1%), neutrophil count decrease (13.1%), and anemia (18.6%). The 18-month PFS rates in patients treated with 200 mg niraparib were somewhat higher than in patients treated with 100 mg after 3-months of therapy. CONCLUSIONS: For Chinese OC patients, niraparib, particularly at a 200 mg individual starting dose, was an effective therapy with easily manageable safety.

Maintenance therapy with poly (ADP-ribose) polymerase inhibitors is a new option for patients with ovarian cancer (OC) after they have received platinum-based chemotherapy to reduce the recurrence or relapse rates, but it remains unclear whether there are any changes in efficacy and safety when different starting doses of niraparib are administrated to Chinese patients, who typically have a bodyweight < 77 kg. We found that niraparib exhibited satisfactory efficacy with tolerable safety during maintenance therapy for advanced OC whether administered at 100 mg or 200 mg doses. We believe these regimens can serve as a valuable addition to the previous results of randomized controlled trials.

The effect of aerobic dancing on physical fitness and cognitive function in older adults during the COVID-19 pandemic-a natural experiment.

During the Coronavirus disease (COVID-19), the physical activity of older adults is at a lower level. The study aimed to examine the effectiveness of aerobic dancing on physical fitness and cognitive function in older adults. We conducted a randomized controlled trial with 34 older adults who were assigned into an aerobic dancing group and a control group. Three dance sessions weekly for 60 â€‹min were scheduled for the aerobic dancing group for a total of 12 weeks. Physical fitness, blood pressure, lipids, glucose, cognitive function were assessed before and after the intervention. Baseline adjusted Analysis of Covariance (ANCOVA) was used to determine whether outcome variables varied between groups at pre-test and post-test. Effect size (Cohen's d) was calculated to determine the differences between groups from baseline to post-test. After 12 weeks, we found that the aerobic dancing group showed significant improvement in memory (portrait memory: F â€‹= â€‹10.45, p â€‹= â€‹0.003, d â€‹= â€‹1.18). The Limit of Stability (LOS) parameters in the aerobic dancing group displayed a significant increase after the intervention (right angle: F â€‹= â€‹5.90, p â€‹= â€‹0.022, d â€‹= â€‹0.60; right-anterior angle: F â€‹= â€‹4.23, p â€‹= â€‹0.049, d â€‹= â€‹0.12). Some beneficial effects were found on flexibility, grip strength, balance and subjective well-being (sit and reach: F â€‹= â€‹0.25, p â€‹= â€‹0.62, d â€‹= â€‹-0.40; grip strength: F â€‹= â€‹3.38, p â€‹= â€‹0.08, d â€‹= â€‹0.89; one-legged standing with eyes closed: F â€‹= â€‹1.26, p â€‹= â€‹0.27, d â€‹= â€‹0.50) in the aerobic dancing group. Aerobic dancing training was effective in improving memory and balance ability in older adults during the COVID-19 pandemic in China. In the future, aerobic dancing is a promising tool to encourage physical activity in older adults.

Rubochingosides A - J, labdane-type diterpene glycosides from leaves of Rubus chingii.

Ten previously undescribed labdane-type triterpenoids, rubochingosides A - J (1-10), were isolated from the leaves of Rubus chingii Hu. Their structures were elucidated by spectroscopic and chemical methods. The cytotoxicity of all isolated compounds was tested against five human tumor cell lines (Bel-7402, Caski, BGC-823, A2780, and HCT-116). Among them, compounds 4 and 8 showed cytotoxic activities against Bel-7402 and A2780 cells with IC50 values of 10.43 ± 0.51 and 29.03 ± 2.94 µM, respectively; Compound 8 exhibited cytotoxic activities against Bel-7402 and HCT-116 cells with IC50 values of 17.78 ± 1.54 and 26.23 ± 6.14 µM, respectively.

Potential effects of oasis expansion on ecosystem service value in a typical inland river basin of northwest China.

To satisfy an increasing need for living space and food while preserving ecosystem services remains one of today's biggest challenges. Oases in arid areas have gradually become the main sources for new cultivated land, affecting the supply and transmission of ecosystem services. Yet, little assessment on predicting the effects of oasis expansion on ecosystem service value (ESV) has been available to guide policy makers and ecologists. Here we addressed the connections between oasis expansion and ESV in the middle reaches of the Heihe River Basin in northwest China by linking the Logistic-CA-Markov model and the benefit transfer method. The results showed that the oasis was expected to expand by 419.02 km2 from 2015 to 2029, with the area of farmland and construction land increasing by 18.87% and 39.05%, respectively. With oasis expansion, the total ESV was expected to increase by 104.25 million RMB from 2015 to 2029. However, oasis expansion encroaches on vegetation, resulting in decline of the values of climate regulation, waste treatment, and biodiversity protection. This study will provide a reference for decision-making in trade-offs involved in land management.

The Effects of Active Video Game Exercise Based on Self-Determination Theory on Physical Fitness and Cognitive Function in Older Adults.

BACKGROUND: Aging and physical inactivity are associated with declines in physical fitness and cognitive function. Active video games have proven to be beneficial for the physical health of older adults, but the exact effect of active video games on physical fitness and cognitive function was still unclear. Based on self-determination theory (SDT), which is a widely used theory of healthy behavior change, this study aimed to explore the effects of an active video game intervention on fitness and cognitive function in older adults. METHODS: A total of 38 participants (mean age = 65.68 ± 3.78 years, 24 female) were randomly assigned to either an intervention group (active video game training) or a control group (no additional intervention). The participants in the intervention group trained for a total of 36 sessions (3 times per week for 50-55 min each) for 12 weeks. The control group continued with their normal daily living. The pre- and posttest measurements included: IPAQ-C score and physical fitness (BMI, body fat percent, blood pressure, reaction time, sit and reach, vital capacity, grip strength, static balance, blood biochemical tests for liver function, kidney function, blood lipids, glucose and insulin levels) and cognitive functions (processing speed, spatial ability, working memory, language ability, associative memory). RESULT: The intervention group showed a significantly smaller decrease in total average physical activity relative to the control group. BMI, vital capacity, systolic blood pressure, diastolic blood pressure, and spatial cognition significantly improved after training in the intervention group (BMI: F = 9.814, p = 0.004, d = -0.93, vital capacity: F = 4.708, p = 0.038, d = 0.67, systolic blood pressure: F = 5.28, p = 0.028, d = -0.68, diastolic blood pressure: F = 6.418, p = 0.016, d = -0.86, spatial cognition: F = 8.261, p = 0.007, d = 0.72). Three measures of static balance (closed eyes) also showed improvements after training (total length of swing: F = 3.728, d = -0.62, total velocity of swing: F = 3.740, d = -0.62, total area of swing: F = 2.920, d = -0.70). No significant training effects were evident in the results from the blood biochemical tests. CONCLUSION: This study indicates a positive influence of active video game training on physical fitness and cognitive function. The use of SDT-based active video game exercise as a feasible, safe, and effective training method for improving community older adults' healthy, promoting group cohesion, and increasing motivation to exercise.

Development and Characterization of Chromosome Segment Substitution Lines Derived from Oryza rufipogon in the Background of the Oryza sativa indica Restorer Line R974

Dongxiang wild rice (DXWR) (O. rufipogon Griff.), which has the northernmost worldwide distribution of a wild rice species, is a valuable genetic resource with respect to improving stress tolerance in cultivated rice (Oryza sativa L.). In the three-line hybrid rice breeding system, restorer lines play important roles in enhancing the tolerance of hybrid rice. However, restorer lines have yet to be used as a genomic background for development of substitution lines carrying DXWR chromosome segments. We developed a set of 84 chromosome segment substitution lines (CSSLs) from a donor parent DXWR × recurrent parent restorer line R974 (Oryza sativa indica) cross. On average, each CSSL carried 6.27 introgressed homozygous segments, with 93.37% total genome coverage. Using these CSSLs, we identified a single QTL, qDYST-1, associated with salt stress tolerance on chromosome 3. Furthermore, five CSSLs showing strong salt stress tolerance were subjected to whole-genome single-nucleotide polymorphism chip analyses, during which we detected a common substitution segment containing qDYST-1 in all five CSSLs, thereby implying the validity and efficacy of qDYST-1. These novel CSSLs could make a significant contribution to detecting valuable DXWR QTLs, and provide important germplasm resources for breeding novel restorer lines for use in hybrid rice breeding systems.

Identification, Analysis, and Confirmation of Seed Storability-Related Loci in Dongxiang Wild Rice (Oryza rufipogon Griff.).

Dongxiang wild rice (Oryza rufipogon Griff.) (DXWR) has strong seed storability and identifying its elite gene resources may facilitate genetic improvements in rice seed storability. In this study, we developed two backcross inbred lines (BILs) populations, with DXWR as a common donor parent and two rice varieties (F6 and R974) as recipient parents. Bulked segregant analysis via whole genome sequencing (BSA-seq) was used to identify seed storability-related loci in the DXWR and F6 population. Two main genomic regions containing 18,550,000-20,870,000 bp on chromosome 4 and 7,860,000-9,780,000 bp on chromosome 9 were identified as candidate loci of DXWR seed storability; these overlapped partially with seed storability-related quantitative trait loci (QTLs) discovered in previous studies, suggesting that these loci may provide important regions for isolating the responsible genes. In total, 448 annotated genes were predicted within the identified regions, of which 274 and 82 had nonsynonymous and frameshift mutations, respectively. We detected extensive metabolic activities and cellular processes during seed storability and confirmed the effects of the seed storability-related candidate loci using four BILs from DXWR and R974. These results may facilitate the cloning of DXWR seed storability-related genes, thereby elucidating rice seed storability and its improvement potential.

[Simultaneous determination of pentostatin and 2'-amino-2'-deoxyadenosine in fermentation broth by high performance liquid chromatography-tandem mass spectrometry].

An analytical method was established for the simultaneously determination the pentostatin and 2'-amino-2'-deoxyadenosine contents in fermentation broth by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After high-speed centrifugation, aqueous solution dilution, vortex shock, and microfiltration, the fermentation broth samples were analyzed by HPLC-MS/MS. The samples were separated on a Waters Atlantis® T3 column (100 mm×2.1 mm, 5 µm) using a gradient elution program with 10 mmol/L ammonium formate (containing 0.1% formic acid) and methanol (containing 0.02% formic acid) as the mobile phases. Moreover, a chromatographic protection column (5 mm×2.1 mm, 5 µm) was added to preserve the column efficiency. The flow rate, column temperature, and injection volume were set at 0.3 mL/min, 25 ℃, and 10 µL, respectively. Qualitative and quantitative analyses of the target compounds were performed using an ESI+ source. MS parameters such as the collision energies and tube lens offsets of pentostatin and 2'-amino-2'-deoxyadenosine were optimized. The quantitative ion pairs of pentostatin and 2'-amino-2'-deoxyadenosine were m/z 269.17>153.20 and m/z 267.00>136.10, respectively; the corresponding collision energies were 11 V and 18 V. The external standard method was used for quantitative analysis. The established method was verified rigorously in terms of the linear range, limit of detection, limit of quantification, recovery rate, and precision. Pentostatin and 2'-amino-2'-deoxyadenosine showed good linear relationships in the range of 1.0-250 µg/L. The correlation coefficients ranged from 0.9969 to 0.9996, and the relative standard deviations (RSDs) ranged from 6.51% to 8.35% (n=8). This result indicated good accuracy and exactitude in the detection of the pentostatin and 2'-amino-2'-deoxyadenosine. The recoveries (n=6) at three spiked levels (1.0, 5.0, and 25 µg/L) were in the ranges of 97.94%-104.46% and 89.96%-107.21% for the pentostatin and 2'-amino-2'-deoxyadenosine, respectively; the corresponding RSDs were in the ranges of 3.74%-4.88% and 4.81%-13.29%. The limits of detection (LODs, S/N≥3) and limits of quantification (LOQs, S/N≥10) of the 2'-amino-2'-deoxyadenosine and pentostatin in the fermentation broth were 0.003-0.060 µg/L and 0.010-0.200 µg/L, respectively. The validated experimental method was used for the detection of actual samples, viz. the stored multiple pentostatin-producing mutagenic strains in our laboratory. The HPLC-MS/MS method for the determination of the pentostatin and 2'-amino-2'-deoxyadenosine in fermentation broth offered the advantages of small sampling volume, strong maneuverability, good stability, and high sensitivity. Compared with previously published methods, this systematically established and optimized method significantly reduced the detection time, and matrix effects were well suppressed. Moreover, the peak shape and stability of the target compounds were greatly improved. This method provides a methodological basis and meaningful reference for the detection of the pentostatin and 2'-amino-2'-deoxyadenosine in fermentation broth.

Safety and feasibility of trial of vaginal labor after cesarean section: A retrospective study.

By observing and analyzing the success rate of Tai'an City central hospital TOLAC and VBNC and various indicators after delivery, we make sure whether TOLAC is safe and feasible to be promoted in Tai'an area.Between January and December 2017, data of 144 cases undergoing TOLAC, 152 cases undergoing VBNC, 152 cases undergoing RCS and 142 case undergoing PCS in Tai'an City Central Hospital were retrospectively analyzed. The success rate of vaginal delivery, labor time, 24 hours postpartum hemorrhage, hospital stay, Apgar score of newborns and puerperal morbidity were observed.Primary study outcomes: The success rates of the TOLAC and VBNC groups were 93.06% and 93.42%, respectively, where the difference was not statistically significant (P = .901). Secondary study outcomes: There were no significant differences in labor time (P = .0249), amount of 24 hours postpartum hemorrhage (P = .206), Apgar score of newborns (P = .582), hospital stay (P = .194) and puerperal morbidity (P = .942) between the VBAC group and VBNC group. There were statistically significant differences in amount of 24 hours postpartum hemorrhage (P < .001), hospital stay (P < .001) and puerperal morbidity (P = .018), but no difference in Apgar score of newborns (P = .228) between the VBAC group and RCS group. There were significant differences in operation time (P = .011), amount of 24 hours hemorrhage (P = .001), hospital stay (P = .001) and puerperal morbidity (P = .041), but no significant difference in Apgar score of newborns (P = .300) between the RCS and PCS groups.The TOLAC is as safe and feasible as VBNC, and more favorable to the safety of mother and fetus than RCS in Tai'an area.

A pre-classification strategy based on UPLC-Triple-TOF/MS for metabolic screening and identification of Radix glehniae in rats.

Traditional Chinese Medicines (TCMs) have gained increasing popularity in modern society. However, the profiles of TCMs in vivo are still unclear owing to their complexity and low level in vivo. In this study, UPLC-Triple-TOF techniques were employed for data acquiring, and a novel pre-classification strategy was developed to rapidly and systematically screen and identify the absorbed constituents and metabolites of TCMs in vivo using Radix glehniae as the research object. In this strategy, pre-classification for absorbed constituents was first performed according to the similarity of their structures. Then representative constituents were elected from every class and analyzed separately to screen non-target absorbed constituents and metabolites in biosamples. This pre-classification strategy is basing on target (known) constituents to screen non-target (unknown) constituents from the massive data acquired by mass spectrometry. Finally, the screened candidate compounds were interpreted and identified based on a predicted metabolic pathway, well - studied fragmentation rules, a predicted metabolic pathway, polarity and retention time of the compounds, and some related literature. With this method, a total of 111 absorbed constituents and metabolites of Radix glehniae in rats' urine, plasma, and bile samples were screened and identified or tentatively characterized successfully. This strategy provides an idea for the screening and identification of the metabolites of other TCMs.

Simultaneous determination of nine coumarins in rat plasma by HPLC-MS/MS for pharmacokinetics studies following oral administration of Fraxini Cortex extract.

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of nine coumarins including aesculin, aesculetin, fraxin, fraxetin, scopoletin, isoscopoletin, 6-hydroxy-7,8-dimethoxy coumarin, 8-hydroxy-6,7-dimethoxy coumarin and umbelliferone in rat plasma using nodakenin as the internal standard (IS). The plasma samples were pretreated by a one-step direct protein precipitation with methanol. The chromatographic separation was carried out on a C18 column with a gradient mobile phase consisting of methanol and water (containing 0.05% acetic acid). All analytes and IS were quantitated through electrospray ionization in negative ion multiple reaction monitoring (MRM) mode. This method was fully validated in terms of the sensitivity, specificity, accuracy, precision (intra- and inter-day), matrix effect, recovery as well as the stability of the analyte under various conditions, and the results satisfied the requirements of biological sample measurement. The validated method was successfully applied to pharmacokinetic study of the nine coumarins in rat plasma after oral administration of Fraxini Cortex aqueous extract, among which the pharmacokinetics of four coumarins including fraxetin, isoscopoletin, 6-hydroxy-7,8-dimethoxy coumarin and 8-hydroxy-6,7-dimethoxy coumarin were studied for the first time.

Deflection tomographic reconstructions of a three-dimensional flame structure and temperature distribution of premixed combustion.

The distribution of premixed combustion parameters and the flame structure were investigated in this work using deflection tomography technology. A deflection tomographic apparatus was presented to obtain chronological arrays of multidirectional deflectograms. The hybrid regularization method was employed to reconstruct the temperature distributions in each cross section. The numerical simulation approach produced reliable reconstructions by computing underdetermined and overdetermined equations for asymmetrical distribution. Visualization technology with the matching cube and ray casting algorithms was applied in three-dimensional visualization. In the work, temperature distributions in five cross sections of the premixed combustion were reconstructed using six view-angle projection data inversions. Three-dimensional flame structures and temperature distributions in the flame interior were visualized using the visualization tool kit.

Simultaneous quantification of six constituents in Qing-huo-zhi-mai tablet by high-performance liquid chromatography-tandem mass spectrometry.

A novel sensitive and specific high-performance liquid chromatography-tandem mass spectrometry method was established for the simultaneous determination of six constituents including geniposide, andrographolide, dehydroandrographolide, ophiopogonin D, methylophiopogonanone A and methylophiopogonanone B in Qing-huo-zhi-mai (QHZM) tablet, a well-known Chinese herbal preparation. The chromatographic separation was performed on a C18 column, and the mobile phase was composed of 0.04% acetic acid and acetonitrile with gradient elution. The detection of analytes was carried out by multiple reaction monitoring scanning with switching electrospray ion source polarity between positive and negative modes in a single run. The total run time was 15 min. The calibration curves were linear with all correlation coefficients >0.9979 in the tested ranges. The intra- and interday variations were no >7.0%, and the average recoveries were in the range of 93.2-108.5% with the relative standard deviations no >5.4%. The developed method was successfully employed to analyze five batches of QHZM tablet samples. This is the first time for the determination of ophiopogonin D, methylophiopogonanone A and methylophiopogonanone B in QHZM tablets.

Simultaneous determination of five constituents in Qinpijiegu capsule by high-performance liquid chromatography coupled with tandem mass spectrometry.

A rapid high-performance liquid chromatography coupled with tandem mass spectrometry method was developed for the simultaneous determination of five constituents in Qinpijiegu capsule (QJC), a classical Tibetan prescription. The separation of five compounds such as aesculin, aesculetin, fraxin, peimine and peiminine was performed on a Purospher STAR LP RP-C18 (250 × 4.6 mm, 5 µm) column with linear gradient elution of acetonitrile-0.3‰ formic acid water in 13 min. Detection was carried out by multiple reaction monitoring mode using electrospray ionization in the positive and negative ion switching mode. The sample was prepared with ultrasound extraction with methanol, which could obtain higher extraction efficiency and shorter extraction time comparing to reflux extraction with alkalized chloroform-methanol. The proposed method was applied to analyze three batches of samples with acceptable linearity (r(2) > 0.9977), precision [relative standard deviation (RSD) < 7.40%], repeatability (RSD < 2.49%), stability [relative error (RE) < 9.15%] and recovery (RSD < 10.76%). This is the first development of a multicomponent quantitation method for the quality control of QJC. Furthermore, the new established method was proven to be highly sensitive and effective in evaluating the quality of QJC.

Structural elucidation of stress degradation products of ampicillin sodium by liquid chromatography/hybrid triple quadrupole linear ion trap mass spectrometry and liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry.

RATIONALE: Clinical adverse reactions to ampicillin sodium are closely related to its impurities and degradation products. Several unknown degradation products have been detected in the degradation samples of ampicillin sodium. Therefore, a sensitive and accurate method is required to rapidly identify unknown degradation products. METHODS: Ampicillin sodium was subjected to forced degradation under hydrolytic (acidic and alkaline), hot, photolytic, and humid stress conditions. A combination of liquid chromatography/hybrid triple quadrupole linear ion trap mass spectrometry (LC/QqLIT-MS) and liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry (LC/QqTOF-MS) was used to identify unknown degradation products. The analysis was achieved with gradient elution on an Agilent Zorbax SB-C18 column using ammonium acetate (1 mmol/L, pH 3.5) and acetonitrile. RESULTS: A total of 19 degradation products and impurities, including five novel degradation products, were identified and characterized in the forced conditions. The novel degradation products were separately identified as (Z)-2-amino-N-((2-oxo-3-phenyl-2,3,6,7-tetrahydro-1H-1,4-diazepin-5-yl)methylene)-2-phenylacetamide (m/z 349), 2-(1-(2-amino-2-phenylacetamido)-2-((carboxy(phenyl)methyl)amino)-2-oxoethyl-5,5-dimethyl-4,5-dihydrothiazole-4-carboxylic acid (m/z 499), (E)-2-(((3,6-dioxo-5-phenyl-1,6-dihydropyrazin-2(3H)-ylidene)methyl)amino)-3-mercapto-3-methylbutanoic acid (m/z 348), 5-(amino(phenyl)methyl)-7-formyl-2,2-dimethyl-2,3-dihydroimidazo[5,1-b]thiazole-3-carboxylic acid (m/z 332), and 2-(1-(2-amino-2-phenylacetamido)-2-((2-(((4-carboxy-5,5-dimethylthiazolidin-2-yl)methyl)amino)-2-oxo-1-phenylethyl)amino)-2-oxoethyl)-5,5-dimethylthiazolidine-4-carboxylic acid (m/z 673). CONCLUSIONS: LC/QqTOF-MS allowed us to obtain more accurate, richer information than LC/QqLIT-MS for the qualitative analysis of unknown compounds. Forced degradation studies could provide us with the data needed to understand the degradation pathways and intrinsic stability of drugs, and to simultaneously validate the feasibility of the analytical procedure.

Multi-responses extraction optimization based on response surface methodology combined with polarity switching HPLC-MS/MS for the simultaneous quantitation of 11 compounds in Cortex Fraxini: application to four species of Cortex Fraxini and its 3 confusable species.

A novel polarity switching high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) approach combining optimization of extraction condition by response surface methodology (RSM) was developed for the simultaneous quantitative analysis of 11 compounds in Cortex Fraxini, a commonly used traditional Chinese medicine. The ultrasonic extraction conditions of the 11 analytes including sample quantity, methanol concentration and extraction time were simultaneously optimized with a Box-Behnken design (BBD) and Derringer's desirability function. Multiple-reaction monitoring (MRM) scanning was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run of 16min. Quantitative parameters of the proposed method with respect to limit of detection (LOD), limit of quantification (LOQ), linearity, precision, accuracy and stability were evaluated under optimum conditions, and the results indicated that the method was sensitive, specific and reliable. The developed method was successfully applied to determine the investigated compounds in four species of Cortex Fraxini and three kinds of its confusable species, and significant differences were found between the official and confusable species.

Simultaneous determination of imperatorin and its metabolite xanthotoxol in rat plasma by using HPLC-ESI-MS coupled with hollow fiber liquid phase microextraction.

The objective of the present study was to develop a new method for the simultaneous quantitation of imperatorin and its metabolite xanthotoxol in rat plasma. The samples were prepared with hollow fiber liquid phase microextraction (HF-LPME). The optimized extraction procedure was acquired by assessing extraction solvent, length of the fiber, agitation rate, extraction temperature and time. A comparison of sample pretreatment ways between HF-LPME and deproteinization with methanol was performed, which demonstrated less ion suppression and better sensitivity of HF-LPME. Analytes were separated on a C18 column with a gradient elution consisted of methanol and water containing 1mmol/L ammonium acetate. The detection was accomplished by electrospray ionization (ESI) source operating in the positive ionization mode. Selected-multiple-reaction monitoring (SMRM) scanning was employed, which guaranteed a higher sensitivity compared with MRM mode. Calibration curves were linear over investigated ranges with correlation coefficients greater than 0.9979. Precision varied from 0.26% to 14%, and the accuracy varied within ±5.5%. The developed method was successfully applied to the pharmacokinetic research of imperatorin and its metabolite xanthotoxol after oral administration of imperatorin to rats.

4-Chloro-anilinium bromide.

In the title compound, C(6)H(7)ClN(+)·Br(-), the amino N atom is protonated. All non-H atoms of the cation are essentially coplanar [r.m.s. deviation = 0.004 (3) Å]. In the crystal, N-H⋯Br hydrogen bonds connect the ions, forming a ribbon-like structure propagating along [010].